Chronic exposure to arsenic-contaminated drinking water is detrimental to human health. We develop an autologistic regression model to evaluate if the geology, pH, and well depth can improve our ability to predict the presence of arsenic at and above detectable levels (≥ 5 µg/L) found in private wells. We use arsenic samples measured in private well water across Gaston County, North Carolina, from 2011 to 2017. We use kriging to map the probability of arsenic at detectable levels across Gaston County. Arsenic at detectable levels was reported at 78 private wells. The median pH for samples containing detectable levels of arsenic was 7.3 and for samples with arsenic < 5 µg/L was 7.1. Our spatial autologistic model suggests that arsenic at detectable levels is positively associated with pH. In addition, private wells set in Mica schist (ЄZms) were associated with arsenic, suggesting a local-scale geologic source influence of arsenic in the county. Our kriging map shows that the northwestern section of the county has more than a 50% probability to have arsenic at detectable levels. In conclusion, based on our results, we recommend increased testing for wells in the Mica schist area. The map of probability of arsenic at and above detectable levels can be used to implement cost-effective targeted interventions.

长期暴露于砷污染的饮用水对人体健康有害。我们开发了一种自回归模型来评估地质，pH和井深是否可以提高我们预测在私人井中可检测水平（≥5 µg / L）及以上砷存在的能力。我们使用2011年至2017年在北卡罗来纳州加斯顿县的私人井水中测量的砷样品。我们使用克里格法绘制了整个加斯顿县可检测水平的砷概率图。据报告，有78口私人井中的砷含量可检出。含有可检测到的砷含量的样品的中值pH为7.3，而砷含量小于5 µg / L的样品的pH值为7.1。我们的空间自体模型表明，可检测水平的砷与pH呈正相关。此外，云母片岩中的私人井（ЄZms）与砷有关，这表明该县砷对当地规模的地质源有影响。我们的克里金图显示，该县西北部的砷含量可检测到的可能性超过50％。总之，根据我们的结果，我们建议对云母片岩地区的井进行更多的测试。砷在可检测水平以上的概率图可用于实施具有成本效益的有针对性的干预措施。